The related known art includes first of all the so-called wind tunnels, which are only employed for aerodynamic studies, and which range from those used to perform laboratory tests on models, to the great structures utilised for aerodynamic tests on real-size automobiles and aeroplanes. They are fed by means of bulb fans. Secondly, there exist wind tunnels used for the physical training of paratroops or parachutists, for military or civilian applications respectively. These are fixed structures, having large sizes and high costs, and are fed by a plurality of parallel fans to insure a suitable flow rate.
Instead, the present invention essentially relates to structures realised for entertainment purposes inside funfairs. For this kind of applications, it is particularly important that the structure be capable of: handling in an optimum manner the streams of participants (in order to insure big profits); insuring the participants' safety: providing adequate means for spectators; preventing participants from being seized by panic (these participants cannot obviously be compared to a skilled parachutist); and providing means for acting promptly, in the latter circumstance. Therefore, it may be noted that problems inherent in such entertainment structures, like the structure of the present invention, are very different from those of a structure used for military training purposes, or from those concerning structures like the wind tunnels employed for aerodynamic studies.
However, turning again our attention, only for a moment, to the general case of wind tunnels and their related technologies, the following patents are worth mentioning: U.S. Pat. No. 5,209,702; U.S. Pat. No. 5,593,352; U.S. Pat. No. 5,753,811; U.S. Pat. No. 6,378,361; and U.S. Pat. No. 6,083,110; the U.S. Pat. No. 6,378,361 having been extended in Europe as EP 1.069.420.
The first of these patents concerns a fixed wind tunnel, including two hydraulic motors. The air flow is adjusted according to the ideal weight (fitness weight) and size of the participant, but no indication is given as to how this adjustment is carried out; moreover, no balance is provided to exactly determine the weight of a person. The fact that this structure is a fixed structure, is a drawback that limits its applications.
The second patent, U.S. Pat. No. 5,593,352, does not disclose stands for spectators, it does not disclose an electric motor, or a change gear (speed gear) for the rotor that generates the flow. It does not take into account any kind of system for accurately determining the participant's weight, which could automatically act on the control of the fan blades inclination, so as to vary the pitch, in order to regulate the air flow.
It is not our intention to discuss in detail all further aspects of the remaining cited patents; instead, we only mention that some of them (the third patent) concern fixed military training structures, while others (e.g. the fourth patent), disclose specific features of a wind tunnel used for aerodynamic studies (having a bulb fan connected to the motor); in any case, all cited patents do not disclose any electric motor driving the fan (rotor) in a controlled manner, and acting at the same time according to two different flow regulation criteria (adjustment of the variable pitch and of the rpm), based on the exact weight of the user.
From the preceding observations it can be concluded that there is currently the need for a structure specifically designed for funfairs, or for similar applications, and which may be fixed, travelling, or transportable, which allows to adjust the air flow based on the exact weight of each user (participant), which optimally regulates the participants streams, which insures the maximum reliability as regards safety, and in particular, which provides for means capable of intervening when a participant is seized by panic, by gradually decreasing the fan flow rate.
Specifically, the flow rate will be gradually reduced during the final period up to the end of the game's turn, before the entry of the next group of participants, whereas it will be gradually increased during the initial period of the game's turn. This kind of system insures the maximum amusement, since the user, after having reached its “flight position”, can be safely and gradually raised up to an optimum height, by the air jet that was automatically computed beforehand, based on the user's weight which was exactly determined by an appropriate balance. At the end of a game turn (that may last for example three minutes), each participant will gradually and safely return to the level of the elastic grid of its flight position, by gradually reducing the air flow rate to a minimum value.
The above objects of the present invention are achieved by means of a structure as claimed in the device.
The main feature of the structure of the present invention, as opposed to the known art, is that the apparatus that generates the air flow consists in a variable pitch rotor (or propeller) driven by an electric motor, whose rpm is controlled by an inverter, and the latter, according to the exact weight (in the form of an electric signal) provided by a balance for determining the weight of the “flying man” (user), varies the frequency of the electric current fed to the electric motor, and consequently, also the flow rate of the air current produced by the propeller, up to a maximum flow rate corresponding to a maximum predetermined height of the flying man above his flight position. This structure has several advantages that will clearly result from the description.
Moreover, when using the inverter it is also possible to gradually reduce—or gradually increase—the rpm (rounds per minute) of the propeller, thereby insuring the maximum safety for the user, and with a minimum percentage error in the rpm value. For other motors, e.g. diesel motors, the rpm is not easily controllable. For instance, the speed change of a diesel motor offers only a limited number of transmission ratios.
Therefore, an electric motor combined with an inverter has remarkable advantages. The electric motor associated with each flight position is operated at a minimum rpm value Nmin—which can be preset—between different game turns, when the participants are getting ready to put on the flight overalls (flight suits) and the helmet, and to weigh themselves on respective balances. This procedure saves the energy required to start again the motors associated with the various flight positions, and lowers at the same time the loads acting on the joint between the driving shaft and the variable pitch propeller. In fact, the greatest loads occur during the start stage. By reducing the loads acting on the joint and on the motor itself, the mean life of these components can be extended.
Other fundamental advantages offered by a structure for funfairs, amusement parks, etc., such as that described in this document, will result from the following more detailed description and when the invention itself is put into practice.